Blood pressure measuring devices are in widespread use to permit persons to undertake self-testing of blood pressure. Typically, these devices are installed in pharmacies, grocery stores, medical clinic lobbies and the like. The machines for taking and displaying the blood pressure data include a pressurization cuff, which is designed to encircle the upper arm of the person undergoing the test. In the past, the pressurization cuff was mounted in a generally cylindrically shaped housing on a spring which biased the cuff to its widest opening within the housing. After the person using the machine inserted his or her arm, the operating sequence for the blood pressure measurement was initiated. The sequence began with an electric motor winding a cloth band, attached to the spring, to tighten the spring carrying the blood pressure cuff around the arm of the person using the device. When the motor had tightened the cuff around the arm, the sequence for inflating a bladder in the cuff and sensing the blood pressure effected by pneumatic pressure in the bladder was accomplished.
The prior art device described above includes a number of components which, after repeated usage, result in the need for continuing maintenance and replacement of worn parts. The electric motor includes a solenoid and clutch for effecting its operation. These parts wear out. Provision must be made to sense the tightness of the cuff effected by the winding of the cloth band on a shaft by the motor. The cloth band, because it is wound and unwound in and out of the device frequently, exhibits wear over a period of time. The continuous flexing and releasing of the springs also creates a potential for mechanical failure.
In addition, the space which necessarily must be provided between one end of the cuff and the end which is moved by means of the winding and unwinding operation of the motor, creates a potential for pinching the flesh of obese or elderly persons in the gap where the flexible cloth band is pulled past the fixed end of the cuff.
It is desirable to provide an automatic blood pressure machine using a cuff which eliminates various mechanical parts of the prior devices, and which is not subject to pinching the arms of obese persons or elderly persons with loose skin.